Aluminum furnace and preheater therefor

Abstract

A reverberatory furnace for melting aluminum or other metals which includes a preheater (12) which utilizes exhaust flue gasses from the furnace (10) to preheat the metal before it enters the furnace. A set of horizontal flue ducts (18, 20, 22) conduct the flue gasses to a preheater chamber (26) where they heat the metal. An air entrance port (50) is provided in the preheater chamber (26) to allow secondary combustion of the volatile flue gasses for additional efficiency.

I claim: 
     
       1. An improved aluminum furnace comprising: a furnace chamber (10) in which aluminum is heated;   an aluminum preheater chamber (26) located adjacent to the furnace chamber (10);   at least one openable door (32,38) opening into the preheater chamber (26) so that material to be melted in the furnace may be introduced therein and removed therefrom;   an exhaust stack (30) exiting vertically from the preheater chamber (26); and   a flue gas duct connecting the furnace chamber (10) to the preheater chamber (26) which includes a furnace exhaust flue (14) provided on the furnace chamber (10) to direct combustion exhaust gases upwardly therefrom, an exit flue junction (18) connected to the exhaust flue (14), a generally horizontal flue duct (20) connected to the exit flue junction (18), a second flue duct junction (22) connected to the horizontal flue duct (20) over a preheater chamber (26), the exit flue junction (18), horizontal flue duct (20) and second flue duct junction (23) conveying the exhaust gases in a generally horizontal direction, and a flue inlet (24) provided on the preheater chamber (26) and connected to the second flue duct junction (22) to convey exhaust gases downwardly into the preheater chamber (26) toward its floor (48) to heat metal therein wherefrom the exhaust gases are drawn upwardly into the exhaust stack (30), whereby the downward conveyance of flue gases into the preheater chamber (26) reduces the effect of the draw from the exhaust stack (30) on the pressure in the furnace chamber (10).   
     
     
       2. An improved aluminum furnace as claimed in claim 1 wherein there is an air entrance port (50) provided in the preheater chamber (26) so as to allow the introduction of some air into the preheater chamber (26) to cause secondary combustion of the gases present in the chamber so as to aid in the heating of any metal in the preheater chamber (26). 
     
     
       3. An improved aluminum furnace as claimed in claim 1 wherein there is a charge well attached to the furnace chamber (10) into which metal to be loaded into the furnace is placed and wherein there is a floor (48) on the bottom of the preheater chamber (26) which is sloped so that molten material thereon flows into the charge well of the furnace chamber (10). 
     
     
       4. A preheater adapted for attachment to an aluminum furnace having a furnace chamber (10), the preheater comprising: an aluminum preheater chamber (26) located adjacent to the furnace chamber (10);   at least one openable door (32,38) opening into the preheater chamber (26) so that material to be melted in the furnace may be introduced therein and removed therefrom;   an exhaust stack (30) exiting vertically from the preheater chamber (26); and   a flue gas duct adapted to connect the furnace chamber (10) to the preheater chamber (26) which includes a furnace exhaust flue (14) on the furnace chamber (10) to direct combustion gases upwardly therefrom, an exit flue junction (18) connected to the exhaust flue (14), a generally horizontal flue duct (20) connected to the exit flue junction (18), a second flue duct junction (22) connected to the horizontal flue duct (20) over the preheater chamber (26), the exit flue junction (18), horizontal flue duct (20) and second flue duct junction (22) conveying the exhaust gases in a generally horizontal direction, and a flue inlet (24) provided on the preheater chamber (26) and connected to the second flue duct junction (22) to convey exhaust gases downwardly into the preheater chamber (26) toward its floor (48) to heat metal therein wherefrom the exhaust gases are drawn upwardly into the exhaust stack (30), whereby the downward conveyance of flue gases into the preheater chamber (26) reduces the effect of the draw from the exhaust stack (30) on the pressure in the furnace chamber (10).   
     
     
       5. An preheater for an aluminum furnace as claimed in claim 4 wherein there is an air entrance port (50) provided in the preheater chamber (26) so as to allow the introduction of some air into the preheater chamber (26) to cause secondary combustion of the gases present in the chamber so as to aid in the heating of any metal in the preheater chamber (26). 
     
     
       6. An preheater for an aluminum furnace as claimed in claim 4 wherein there is a charge well attached to the furnace chamber (10) into which metal to be loaded into the furnace is placed and wherein there is a floor (48) on the bottom of the preheater chamber (26) which is sloped so that molten material thereon flows into the charge well of the furnace chamber (10).